Published: Mon, July 09, 2018
Medical | By

A new HIV vaccine shows positive results in human trails

A new HIV vaccine shows positive results in human trails

Researchers have since launched a phase two trial involving 2,600 participants in southern Africa to continue testing how safe and effective the HIV-1 vaccine is. The mosaic is one of five vaccines to ever make it this far in the testing stages, but none of the previous vaccines were successful enough to make it to the next round of testing.

"These results represent an important milestone". Last Saturday the research bore fruit when a team of scientists announced that a trial drug has shown immune response in humans and also protected laboratory monkeys from HIV infection.

"We expect results in 2021".

"The challenges in the development of an HIV vaccine are unprecedented, and the ability to induce HIV-specific immune responses does not necessarily indicate that a vaccine will protect humans from HIV infection", said Barouch.

A vaccine is a vital weapon in the war against the virus, which infects an 1.8 million people each year.

Meanwhile, the World Health Organization and UNAIDS estimated that there were about 36.7 million people who were living with HIV worldwide at the end of 2016.

"We eagerly await the results of the phase 2b efficacy trial called HVTN705, or "Imbokodo", which will determine whether or not this vaccine will protect humans against acquiring HIV", said Barouch.

In the APPROACH trial of almost 400 participants, researchers conducted a multicenter, randomized, double-blind, placebo-controlled study to assess the safety, tolerability, and immunogenicity of several vaccine regimens in humans. The study, published yesterday, was conducted on about 400 HIV-negative adults from the United States, Thailand, East Africa, and South Africa, but also on 72 lab monkeys.

To stimulate, or "prime", an initial immune response, each volunteer received an intramuscular injection of Ad26.Mos.HIV at the start of the study and again 12 weeks later.

Unlike past efforts, which only focused on specific HIV strains, this vaccine is a "mosaic" that includes pieces of multiple strains in a bid to create a more universal drug.

Barouch and colleagues found that, among 393 participants in the APPROACH trial receiving at least one dose of study vaccine, the mosaic adenovirus serotype 26 (Ad26) plus high-dose gp140 boost vaccine produced the greatest immune responses in humans - with antibody responses in 100% of participants at week 52, and T-cell responses in 83% at week 50. In five people, dizziness, diarrhoea and back pain were among the most severe symptoms. No grade 4 adverse events or deaths were reported. He explained that more data needs to come in from human trials to deem this as safe and protective against HIV infection.

They carried out parallel studies in rhesus monkeys and humans to define "the optimal vaccine regimen to advance into clinical efficacy trials".

"The road to the clinic is still unpredictable since the exact mode of action in humans is still unknown and the 67 percent protection in monkeys might not be replicable in humans", said George Williams Mbogo from the Burnet Institute in Australia, who wasn't involved in the study.

This doesn't mean that the group has found an effective vaccine.

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